GNOME Bugzilla – Bug 160179
Clicks inserted into mulawenc encoded output
Last modified: 2005-08-29 15:43:40 UTC
Transcode an audio file using the following command: gst-launch filesrc location="restore-donormessage1.wav" ! wavparse ! audioconvert ! audioscale ! mulawenc ! audio/x-mulaw,channels=1,rate=8000 ! filesink location="restore-donormessage1.ulaw" The resulting file has a series of regular clicks where it appears that mulawenc is replacing data in the output stream with null bytes. A similar problem can be seen if I had used alawenc or gsmenc. Source file: http://svr1.ocjtech.us/restore-donormessage1.wav Result file: http://svr1.ocjtech.us/restore-donormessage1.ulaw Here is a screenshot that compares the files in Audacity: http://svr1.ocjtech.us/Screenshot-restore-donormessage1.png I imported both the source file and the result file into Audacity. I then duplicated the result file track and shifted the duplicate track to the right by about 2.4s. I'm using the gstreamer yum repository.
Hmmm... with the help of BBB on #gstreamer determined that the problem is likely not in mulawenc because using a MP3: gst-launch filesrc location=x.mp3 ! mad ! audioconvert ! audioscale ! mulawenc ! audio/x-mulaw,channels=1,rate=8000 ! filesink location=x.ulaw works fine.
I would guess the clicks come from audioscale. I had the same problem because of invalid reads in libresample (see bug 159211).
Can you please test that, Jeffrey?
The patch from bug 159211 appears to fix my problem, at least on the test case mentioned above. I'll continue testing but for now I'll mark this bug as a duplicate of bug 159211. *** This bug has been marked as a duplicate of 159211 ***